Map data distribution system and map data updating method

Abstract

A map data distribution system includes a server which distributes map data and a mobile terminal which receives the map data. The server stores, for each area, the difference data between pieces of map data obtained before and after updated, and sends the difference data of map data of an area requested by the mobile terminal to the mobile terminal. The mobile terminal includes a database for storing map data and an updated-data store part for storing updated map data, generates updated data by using the received difference data, stores the updated data in the updated-data store part and then in the database. To fetch map data while the updated data is being stored from the updated-data store part to the database, when the map data to be fetched is stored in the updated-data store part, the mobile terminal fetches the map data from the updated-data store part.

Description

CLAIM OF PRIORITY[0001]The present application claims priority from Japanese patent application JP 2007-182018 filed on Jul. 11, 2007, the content of which is hereby incorporated by reference into this application.FIELD OF THE INVENTION[0002]The present invention relates to a technique of updating map data stored in a mobile terminal.BACKGROUND OF THE INVENTION[0003]In navigation systems, in a case where a part of map data stored in a server is updated, when only the part of the map data is updated in a mobile terminal, a navigation function may not be properly performed. For example, when a new road is constructed in an update target area, the road included in the area, whose map data has been updated, may not be connected to roads included in areas which are contiguous to the update target area and whose map data has not been updated. To address this problem, JP-A-2004-177245 discloses a technique which ensures road connectivity by expanding, along the changed road, the update tar...

AI Technical Summary

Benefits of technology

The present invention provides a map data distribution system that allows for the use of map data even when a long processing time is required to create indexes. The system includes a data distribution server and a terminal. The server stores map data and difference data between map data before and after update. The terminal generates updated data by applying the difference data to the map data and stores it in a database. The system allows for quick reference to map data even when updating the indexes is a long process. This is achieved by accessing the updated data stored in the database and writing it in a separate updated-data store part. The technical effect of the invention is to allow for efficient use of map data in a database distribution system.

Problems solved by technology

However, since areas included in the expanded update target area must be updated at the same time, a long processing time is required to handle the wide update target area.

Since map data cannot be referred to while update processing is being performed, the map data cannot be referred to for a long time.

If map data of Japan is divided, for example, in units of several kilometers, several tens of thousands of files need to be managed and a large load is imposed when the map data is referred to.

If the update target area is wide, a long time is required to update the indexes, and, as a result, the map data cannot be referred to for a long time.

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